Jesse Sumner Cowles was born around 1845 to Sarah and Montgomery Cowles in Albemarle County, Virginia. Cowles had been a slave in eastern Virginia before the Civil War. When the Union army marched up the Virginia Peninsula toward Richmond in the summer of 1862, Cowles escaped slavery and fled to Union lines, becoming part of a mass wartime exodus of fugitive slaves to the Federal army. His family continued to live in the Williamsburg area during and after the war.

Cowles enlisted as a private at the age of 18 on November 30, 1863, in Hartford, Connecticut, and mustered in on March 8, 1864, in New Haven. His service record describes him as 5 feet, 5 1/2 inches tall, with black hair, black eyes, and dark complexion. Cowles served in the 29th Connecticut Infantry Regiment. With the 29th Connecticut, Cowles served throughout the South during the war, including at the siege of Petersburg and Richmond in 1864 and 1865 as well as in Maryland and Texas. Cowles received a wound to his left forearm at the Battle of Kell House (Second Fair Oaks), Virginia, on October 27, 1864. He mustered out with the rest of his regiment on October 24, 1865, in Brownsville, Texas.
 
After the war, Cowles made his way north to Connecticut, where he graduated from Wesleyan University and was ordained as a minister in 1872. In the early 1870s, he placed ads in several newspapers seeking information on his mother's and siblings' whereabouts. He eventually reconnected with at least two of his brothers, William and Carter. He played a leadership role in AME Zion churches in postings across the North. He used his considerable talents as an organizer and orator to support charitable causes, to protest segregation and other forms of discrimination, and to keep the memory of the Union victory alive. In 1885, Cowles' congregation in New York raised $15 to help build President Ulysses S. Grant's mausoleum. The monument committee noted that this was the "first subscription from any organization of the colored people of the U.S.," and they invited him to serve on the committee. 

He married Nancy (Nannie) Cowles on March 8, 1876. The couple had no children of their own, but they adopted two daughters: Etha, born around November 1884; and Clara, born around December 1886. He applied for a federal pension in August 1874, and he eventually began receiving $4 per month. Government officials increased his pension to $10 per month in 1890. He became a prominent figure in the York, Pennsylvania, community, and a local writer described him as an "earnest and faithful worker and an eloquent and pleasing pulpit orator." His wife died on November 4, 1896, and he died of consumption on July 17, 1897. 

Documents:

Jesse S. Cowles Raises Money for Grant Monument Association

Jesse S. Cowles Joins Grant Monument Committee

Description of Jesse Cowles's Work as a Minister

Funeral of Jesse S. Cowles

Jesse Cowles Searches for His Family